One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,4,3)(7,11)(10,12)(13,14)(15,19)(16,23)(17,18)(20,22)(21,26)(24,25)(27,28)(2,3)(6,9)(7,11)(13,15,18,22)(14,20,17,19)(16,24,25,23)(21,28,27,26)(5,6)(7,10)(8,9)(11,12)(13,16)(14,21)(15,23)(17,27)(18,25)(19,28)(20,26)(22,24) involution — undirected(1,3,4,2)(6,9)(10,12)(13,17,18,14)(15,20,22,19)(16,21,25,27)(23,28,24,26)(5,7,8,11)(6,10,9,12)(14,17)(15,22)(21,27)(23,24)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.